In general, a bill processing apparatus, which is one of the embodiments of the paper sheet processing apparatus, is incorporated into a service device such as a game medium rental machine installed in a game hall, a vending machine or a ticket-vending machine installed in a public space, or the like which identifies the validity of a bill inserted from a bill insertion slot by a user and provides various types of products and services in accordance with a value of the bill having been judged as valid. Such a bill processing apparatus comprises a bill conveyance mechanism that conveys a bill inserted into a bill insertion slot, operation equipments such as a bill identification part that conducts validity judgment (or also referred to as authenticity judgment) whether the bill to be conveyed is valid or not, etc., and control means which drives and controls such operation equipments.
Here, the bill identification part is configured to read a bill in a traveling state by an identification sensor such as a line sensor, to compare its output with legitimate data having been stored in advance, and to judge the validity. In order to read all bills at a uniform level, it is required to convey the bills in an exact state that the bills are not allowed to pass obliquely (to correct inclination of the bills to a traveling direction, hereinafter being referred to as “skew correction”). Further, since widths of bills may be different by the kind of the bills, it is necessary to feed a bill into the bill identification part as the bill is exactly and accurately positioned (e.g., centering and the like).
As a bill processing apparatus having a skew correction mechanism that positions a bill in an exact state with respect to the bill identification part as described above, such a configuration is disclosed, for example, in Patent Document 1 and has been known. In this known technology, a pair of movable pieces, each of which has a cross section of a general U-shape, is provided on a bill traveling route so as to regulate both side edges of a bill to be conveyed, and an alignment motor is driven at a stage that the bill is located between the pair of movable pieces so as to move the movable pieces in directions such that both pieces come closer with each other. Then, the pair of movable pieces driven to move in such directions that both pieces come closer with each other by the alignment motor touch both side edges of the bill and deformation resistance force of the bill becomes greater than that caused by holding torque of the alignment motor such that step-out or skidding occurs in the alignment motor, whereby the pair of movable pieces cannot move such that the center of the bill is aligned to the center of the traveling route (skew of the bill is also eliminated at the same time).
[Patent Reference 1] Japanese unexamined patent application publication No. 2002-279487